I'm sure we had a 123d auto a few years that had been tuned by another company already that did this and when we put it back to standard it was fine
We then tuned it our way and it never did it

Who have your cars been tuned by ?

BW chiptune
Tuning BMWs since 1991
Dyno Dynamics rolling road.
BW autorepairs
Over 30 year repairing BMWs.
New and fully refurbished BMW/Alpina ,Ecus (DME,DDE)and Cas units.
BMW Ecu repairs.
BMW remote Keys made and cut same day with or without car even if all keys lost we can supply you a key like the dealers do.
Key data fixed for non starters or when theft attempted.
Correction of Engine ECUs Cas and key fitted to your car (when a key set from a different car has been used).
Digital Service Records rest and corrections in idrive screen on 2013 onwards cars.
DPF repairs fixed without the need of removal of its guts or replacement.
40% of my work is repairing the problems that are caused by other tuners remap